Heat exchanger made from punched plates



y 6, 1952 w. w. AUSTIN 2,595,440

HEAT EXCHANGER MADE FROM PUNCHED PLATES 2 SHEETS-SHEET 1 Filed July 8, 1950 INVENTOR. [Ml/mm M4 Alla/m ATTORNEY May 6, 1952 w. w. AUSTIN HEAT EXCHANGER MADE FROM PUNCHED PLATES 2 SHEETS-SHEET 2 Filed July 8, 1950 ATTORNEY Patented May 6, 1952 HEAT EXCHAN GER MADE FROM PLATES PUNCHED William W. Austin, Wellsville, N. Y., assignor to The Air Preheater Corporation, New York, N. Y.

Application July 8, 1950, Serial No. 172,650

1 Claim. 1

The present invention relates to heat exchange apparatus and particularly to improvements in plate type exchangers utilized for the transmission of heat between two confined fluids.

One well known form of heat exchanger for the transfer of heat between two confined fluids is made up of a plurality of spaced metallic plates forming passages through alternate ones of which a heating fluid, such as a hot gas, flows in heat exchange relationship with the fluid to be heated. such as air, traversing the intermediate passages. The present invention contemplates providing the passage walls through which heat is exchanged with pin-like fins constituted by the ligaments between perforations in rows punched in metallic strips which after being centrally dished or depressed are bonded together to form not only the fin elements but the walls of the passages in which they are located.

The invention will best be understood upon consideration of the following detailed description of illustrative embodiments thereof when read in conjunction with the accompanying drawings in which:

Figure 1 is a perspective view of a portion of a plate type heat exchanger having a series of heat exchange envelopes embodying the present invention.

Figure 2 is a perspective view of one of the basic elements of the heat exchanger, shown as consisting of a metallic plate punched with a row of perforations.

Figure 3 is a perspective view illustrating the plate of Fig. l in a second stage in which the central portion thereof has been dished or depressed.

Figure 4 shows a pair of plates of Fig. 3 mounted back to back to form one of the finned components from which the heat exchange envelopes are constructed, the view being in section.

Figure 5 is a transverse sectional view through a finned heat exchange envelope made up of a plurality of the components shown in Fig. 4.

Figure 6 is a side view corresponding to Fig. 5.

Figure '7 is a fragmentary sectional plan view showing the manner in which the air passages of the heat exchanger are connected with the inlet and outlet headers for air.

Figure 8 is a fragmentary perspective view illustrating one manner of providing the flow defleeting vane shown in Fig. 7.

Figure 9 is also a fragmentary perspective View showing flow plates mounted in the portions of the air passage traversed by fluid flowing transversely of the finned components at the inlet and outlet ends of the passages.

Figure 10 is a fragmentary perspective view of a further arrangement for connecting the air passages to the inlet and outlet headers.

The heat exchanger of which a part is shown in Fig. 1 is basically of the plate type wherein spaced metallic plates form air and gas passages arranged in alternation so that the heat of gas, for example, flowing in alternate passages is transmitted through the intervening plate walls to air passages on either side of and intermediate .the gas passages. In accordance with the present invention a plurality of so-called envelopes are formed which consist essentially of a pair of spaced plates defining opposite boundaries of an air passage with the spaces at the side edges of the plates being bridged by closure members which combined with the plates form a rectangular envelope open at opposite ends for connection to the inlet and outlet manifolds. The plates have extended surface in the form of fins projecting into the air passage and to build up a heat exchanger a plurality of these envelopes are superimposed upon each other and maintained separated by suitable spacer members to form the intermediate gas passages.

In accordance with this invention the basic element of the heat exchanger consists of a metallic strip somewhat greater in length than the passages to be traversed by the fluids between which heat is exchanged. In the first operation the metallic strip I0 shown in Fig. 2 has a plurality of closely spaced perforations l2 punched therein in a single row extending longitudinally of the strip. The plate ligaments remaining between the perforations after formation of the latter constitute a plurality of pin-like fins I4 for the walls of the air passage of the heat exchange envelope as will be apparent from consideration of Fig. 1. In a second operation the perforated plate of Fig. 2 has its central portion dished, depressed or bent along lines AA, B-B close to each side of the row of perforations and parallel to its axis so that the fin parts "4 become disposed in a plane parallel to and spaced from by the shoulders 23 the remaining portions of the strip which now assume the form of raised lateral flanges 16 on the strip. A pair of the dished strips of Fig. 3 are then mounted back to back Fig. 4 with the strip portions H3 at and along opposite sides of the row of perforations l2 in contact with each other and they are then integrally joined together as by seam welds between these parts at 20.

To construct a heat exchange envelope a series of the components shown in Fig. 4 are mounted passage while the plate ligaments separating the perforations I2 become pin fins l4 projecting from these walls into the air passage and bridging the latter at intervals. At the same time the flange portions I6 of the components become longitudinally extending fins disposed in what will be the gas passages at either side.

A plurality of envelopes such as shown in Fig. 5

havingbeenconstructed, they are mounted in superposed relation (Fig. 1).with' the space between their side edges closed by members 38. Qther members 3i not only space the envelopes but serve to form the side closures forthe intermediate gas passage. of sufilcient'height to maintain the longitudinal flange-like fins 16 of adjacent envelopes out of contact along their longitudinal edges. The ends of the gas passages provided in the envelopes themselves are connected in conventional manner to the inlet and outlet manifolds. The endsof the air passages are closed as shownin Fig-6 by the plates or strips 33 which have a series of spaced bosses or projection 34 to fit within the section of the subdivisions of the gas passage created by I thefins 1 4 bridging the latter.

The other fiuid such asair to.be heated is.

admitted from the sideof the heat exchanger as shown in Figs. 1 and? to 10.. As.sh'own. in Fig. 1 the envelopes extend somewhat Ibeyond theair P3r$fl$f3SIQIQPI and the dished parts are formed- 'urith. a ;sei ies of relatively largeopeningssfi with :an-imperforate portion 38. at the outer end.

Thereis progressively one less opening 36 in each ish portion transversely, of the exchanger in. the

],direction proceeding from the side at which the ,air inlet header is located.

Asshownin Figs? ands guide strips 40 are fitted through the openings36 in the longitudinal fins-l6 and extend transversely of the airpassage in inclinedrelation so as toguide and distribute the air uniformly across the air passage into the various channels into which the passage is divided by thefins'IB. Theguide strips 40 are of progressively longer 'length so that the fluid is divided into a series "of-streamseach of which is led directly to one of the channelsor subdivisions inthe air passage formed between the longie tudinally extending finsl4.

To provide pin fins in the air passages the longitudinal flanges l6 are formed with a plurality of perforations 44 so that the intervening .plate These side closures 3| are ligaments 48 constitute pin fins or may be said to provide an interrupted strip fin in the air passage.

In the form shown in Fig. 9 a flow plate 50 is attached to the side of one of the components and located in the passage to bridge the valley or gap 52 between the ligaments 18 .extending from the passage walls 26; 28between the pin fins l4 so as to reduce pressure drop.

In Fig. 10 instead of utilizing the guide strips shown in Fig. 8, rectangular tubes 56 are fitted through the openings. I2 to lead the air streams directly to the channels formed in the passages. Herethe series of perforations 36 are near the outer endsof the flanges because the tubes would traverse several fins and those for the inner channels would otherwise block flow to outwardly located channels.

What I claim is:

A heat exchange envelope of the type having spacedwalls defining a' passage for circulation of one fluid in'heat exchange relationship with anotheryfluid flowing in" contact with the outer surfaces ofsaidwalls comprising; aJplurality of metallic stripseachpunched witha row of closely spacedperforations and centrally dished or bent along lines paralleling the axis of said row of perforations and closely adjacent. the latter to form a. pairiof lateralflanges alongeach'edge of the strip spaced from the body thereof by substanti'a'lly,perpendicular shoulders,. said strips.

beingmounted in. pairsib'ack to back withthe central dishedportions bordering the rows of perforations .iri contact and bondedtogether and a plurality. of; joined; pair, components mounted in abutmentfin arow with. the outer faces .of. their; lateral. flanges. bonded together to form an envelope having a central passage .with.

the strip ligaments between the perforations constituting pini-likefins extendingfrom the passage walls-constituted by saidishoulders of the dished portionsof the strips and with. the lateralfianges of the strips constituting longitudinal fins on the outer faces-of the passage walls for contact with the other fluid} and means at the sides of said envelope bridging the spaces-between the walls formed by abutment of Said components forclosing the envelope at its side edges.

WILLIAM AUSTIN.-

REFERENCES" CITED The following references .are of record .in the file of'this patent:

UNITED STATES PATENTS Number. Name Date 1,680,673 Fedders Aug; 14, 1928 2321.110 Shipman June 8, 19.43

FOREIGN @PATENTS Number Country Date 574,210 Great Britain Dec. 27, 1945 being I 

